Originally Posted by ChaoticAtmosphere
Only thing I can think of is the HDD, but you said you can get to the desktop in safe mode. I would check the event log in safe mode with networking and see if you can find any error codes and troubleshoot from there.
Try aboot into windows normally then when it doesn't boot (note the time) then boot into safe mode with networking and check the event log.
If that yeilds no results my next step would be back up important files to a network drive and do a fresh install.
I would do the same, if Ubuntu and windows can't boot, I would backup everything, and test everything:
-Stress test CPU, GPU, etc..